It is known to provide various designs of the end caps and bearing assemblies directed to improve safety of operation of belt conveyors in hazardous environment.
According to Czechoslovak Author's Certificate 248,200, each end of the axle of a conveyor roller has an axle section which supports an antifriction bearing provided with knurling. Located exteriorly of the bearing is a rubber seal with sealing lips and with protective stamped metal sheet members. While providing relatively good sealing effects against penetration of dust and other impurities into the bearing mount assembly, the arrangement does not prevent the contact of red-hot parts of a seized bearing with the ambient atmosphere, which increases the fire or explosion hazard.
In the arrangement according to Czechoslovak Author's Certificate 249,678, bearings are located in inner openings of profiled end members. The end members are firmly connected to each other by a connecting spacer tube. Each bearing is provided, at the outwardly directed side, with a two-part sealing labyrinth the position of which on the axle is limited by a snap ring. The labyrinth seal is separated from the surroundings by means of a corrugated lid or a dust cap. The position of the dust cap is fixed by an inserted expansion ring. The end cap is provided with a profiled shield or cover to prevent damage to the seal assembly of the bearing. A similar principle is utilized in Canadian Patent 1,187,030, where the corrugated lid is replaced with a removable sealing cover. The disadvantage of these structures is in that they do not entirely secure the operation of the sealing assembly in extreme operation conditions, which increases the need of checks and limits their applicability, e.g. in mines or other potentially explosive environments where, in case of the seizing of the bearings, it is necessary to stop the belt conveyor which gives rise to substantial operation losses.